How To Get Rid Of Constipation?

Good evening, I am a female of 64 years. (actually, I have always been a female) For the last week I had been constipated so last night at 10:00 P.M. I took a laxative. Something I rarely do. Very rarely. This morning I began evacuating, normally. This went on for the entire day. My stools when from normal brown to black and rather textured, as in sandy like. My stomach was destented and quite sore. It still is, actually. I weigh 115 lbs. and am 5 4 tall. I have lost about fifteen pounds recently, with no effort. Food makes me ill after a few bites and my stomach hurts in the lower intestine area, constantly. I am still experiencing pain and the urge to evacuate. I am concerned and cannot reach my doctor. I was told to go to the emergency room if I felt it was necessary. I have not taken Pepto or any other medication out of the ordinary. However, I am under a great deal of stress as my husband is very ill and we are in foreclosure on our home and I am job searching. Other than that, my life is great! Please advise. Thank you, Rebecca W. Reeves